memset problem

[Rajesh1978]

Hi,
Sorry for putting a c code.

I am trying to use memset. But it is behaving in a strange manner.

int main()
{
	 char arr[99];
	 char tt[] = "hello";
	 
	 memcpy(arr,tt,5);
	 memset(arr+5,' ',94);
	 printf("%s",arr);
	 return 0;
}

The out put is giving hello blank space and some junk at the end.

But as per my knowledge it should only print hello.
I am using vs2005.

Please clarify

[Alex F]

You need to add 0 in the end of string, and not space:
memset(arr+5,0,94);

[Rajesh1978]

Thanks Alex it worked.

But one thing i want to know when i used memcpy(arr,tt,5); tt is null terminated so does the memcpy do not copy the null here

[GCDEF]

Hi,
Sorry for putting a c code.

I am trying to use memset. But it is behaving in a strange manner.

int main()
{
	 char arr[99];
	 char tt[] = "hello";
	 
	 memcpy(arr,tt,5);
	 memset(arr+5,' ',94);
	 printf("%s",arr);
	 return 0;
}

The out put is giving hello blank space and some junk at the end.

But as per my knowledge it should only print hello.
I am using vs2005.

Please clarify

What are you trying to accomplish there? Why not just use strcpy?

[GCDEF]

Thanks Alex it worked.

But one thing i want to know when i used memcpy(arr,tt,5); tt is null terminated so does the memcpy do not copy the null here

You told it to copy 5 bytes. The null is in the sixth position.

[Rajesh1978]

I was trying to understand the behaviour of memset and memcpy.

I had a misconception that it will not copy the null character.

thanks

[THEARTOFWEB]

btw if I were you I'd always initialiaze vars with something:

char arr[99] = {0};

[treuss]

You told it to copy 5 bytes. The null is in the sixth position.

And even if you had copied at, you would have overwritten it with a space next.

[kempofighter]

I was trying to understand the behaviour of memset and memcpy.

I had a misconception that it will not copy the null character.

thanks

It copies whatever you tell it to copy. hello is 5 bytes. You told the memcpy to copy 5 bytes. If you wanted it to copy the NULL then you tell it to copy 6 bytes. Or you do as others have suggested and use strcpy. memcpy doesn't care what is in the source memory block. It copies exactly how many bytes you tell it to copy irrespective of what is contained within that source memory block.